Optimal RF flip angles for multiple spin-echoes and iMQCs of different orders with the CRAZED pulse sequence

Optimal RF flip angles of the NMR CRAZED pulse sequence for multiple spin-e choes (MSEs) and intermolecular multiple quantum coherences (iMQCs) of diff erent orders were investigated theoretically and experimentally. An analyti cal expression for the dependence of signal intensities on RF pulse flip an gles was derived for the cases when higher-order expansion terms of Bessel functions can be neglected from a combination of dipolar demagnetizing fiel d treatment and product operator formalism. Theoretical predictions for bot h the relative signal intensities and the optimal flip angles at which the signal intensities are maximized are found to be in excellent agreement wit h experimental results. (C) 2001 Elsevier Science B.V. All rights reserved.